Zebrafish are good models for human disease

Recent studies show zebrafish to be a useful animal model in studying mental illness and neurological diseases.

Zebrafish are a tropical freshwater species used to study vertebrate development and gene function. In 2008, the UK used approximately 605,000 fish for research purposes, an 85% increase on the previous year. Their importance and usage is increasing because scientists are finding more ways in which the species can help in the understanding of disease, and even replace higher animals in research.

Now researchers have revealed that zebrafish can be used to investigate treatments for mental and neurological diseases. Zebrafish have a similar brain chemistry to humans which has made them useful in testing responses to new medicines. One team tested many different compounds on zebrafish embryos and studied their response to light and movement. Another team investigated the effects of medication on sleep-wake cycles of zebrafish larvae.

Both groups found that each medicine had a unique behavioural effect like a ‘fingerprint'. Similar fingerprints, producing the same type of behaviour, used the same biological pathways. Because of the chemical similarities between the brains of zebra fish and humans, these findings suggest the animals make good models to study how these medicines would affect the human brain.

The anatomy of zebrafish is simple and therefore easy to study. The embryo is uncomplicated and develops quickly. Once mature they can breed within 2-3 months and a female can produce as many as 200 eggs per week. They are particularly useful in genetic studies as their DNA has many similarities with the human genome, despite being half the size and reproducing so fast.

Scientists hope to use zebrafish models to further study diseases such as Alzheimer's disease and sleeping disorders using chemicals they identified as possibilities through this research.